#include <stdio.h>
#include <time.h>
#include <string.h>

int sleep(unsigned ms) {
    clock_t s = clock();
    clock_t e;

    do {
        if ((e = clock()) == (clock_t)-1)
            return 0;

    } while (1000.0 * (e - s) / CLOCKS_PER_SEC < ms);

    return 1;
}

int main(void) {
    char *str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    int i =0;


    for (; i < strlen(str); ++i) {
        putchar(*(str+i));
        sleep(500);
        fflush(stdout);
    }

    for (; i>=0; --i) {
        printf("\b \b");
        sleep(150);
        fflush(stdout);
    }

    putchar('\n');

    return 0;
}


